Sony STR-DE635 No Sound.

[jamil5454]

My friend just gave me his old receiver because it wasn't working. I figured if I can fix it I'll myself a free surround receiver. It's a Sony STR-DE635.

I'm suspecting the amp is blown somewhere, because the unit turns on fine, switches inputs, detects digital signals fine, etc... except I get no sound. I tried all of the speaker terminals and the front headphone jack. I opened it up and checked the visible fuses, and they all appear to check out ok. I don't notice any immediate problems after looking over the circuit boards for a few minutes.

With my headphones plugged in to the front and the volume all the way up (coax source from DVD player) I can hear some white noise coming through. This noise gets noticeably louder if I put on the bass boost.

He said it was working fine until recently, when he moved and tried to hook it up to a 4-speaker system and his TV. He had the wiring all messed up, so let me explain a little:
The front left speaker and rear left speaker cables were twisted together. Same with the front right and rear right. These cables were then connected to front output A, so that each output terminal was driving two speakers. To make matters worse, he ALSO had two cables coming from the built-in TV amp to the receiver, so that there were a total of 3 wires in each terminal of front output A. Now, we were playing music from the TV, and it worked great (the receiver was turned off), but then I noticed his receiver was messed up. I tried to get the cables hooked up correctly but to no avail. The TV amp was turned up quite loudly.

As a side note, the TV doesn't work anymore either. It sort of "blips" when you turn it on, making a short blipping noise every half second. You can turn it off, but it won't come on again until you unplug it.

I'm hoping the problem with the receiver is maybe a blown transistor somewhere. I can provide pictures of any component upon request, and if anyone would like the schematic I can post a link to that as well. Otherwise, I appreciate any help anyone is willing to give on this matter and I'll keep you guys updated for others who may be having similar problems.


P.S. -- If it helps, my car stereo behaved exactly the same way after I shorted the speakers wires together with it turned on, so that may be a clue.